


Sweet Dreams

by Tarash



Category: Gravity Falls
Genre: Adult Dipper Pines, Aged-Up Character(s), Anal Sex, BillDip, Dream Sex, If this doesn't sound like your thing don't read it, M/M, Non-Consensual, Other, Plot What Plot/Porn Without Plot, Tentacle Bondage, Tentacle Rape, Tentacle Sex, Tentacle handjob, Tentacles, dirtybadwrong, triangle!Bill
Language: English
Status: Completed
Published: 2015-09-27
Updated: 2015-09-27
Packaged: 2018-04-23 17:31:28
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 3,051
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4885558
Author URL: https://archiveofourown.org/users/Tarash/pseuds/Tarash
Summary: <blockquote class="userstuff">
              <p>Even at college, Dipper still has dreams Bill Cipher appears in. </p>
<p>And then, one night, Bill decides on a different tactic to persuade Dipper to give in and make a deal.</p>
            </blockquote>





	Sweet Dreams

**Author's Note:**

> So basically I figured that having Bill be able to turn his limbs into tentacles (he's a dream demon, you can do anything in a dream, after all) and use those tentacles on an adult Dipper would be fun. I hope you like it too :)
> 
> (Also I tagged it as M/M and Other because WTF even is Bill.)

He still has the dreams.

_“I’ll be watching you…”_

 It’s been years, and he still has the dreams.

 There’s no pattern. They can be dreams about his summers in Gravity Falls, high school, or the one where he can fly and he’s half-excited and half-scared he’s gonna plummet to his death.

 There’s a warning sign, though, and he’s learned to look out for it. Triangles, however, are pretty much everywhere, and more than once he has spent a dream being worried and anxious without there being any need for it.

 And then, he hears it.

 “Miss me, Dipper?”

 The alarmingly cheerful voice, the bright yellow. It’s Bill. Again.

 “No,” he replies, as usual. No matter where Dipper was in his dream, Bill always likes to take him back to the woods of Gravity Falls.

 Bill laughs. “You’re so funny!”

 Dipper glares up at the triangle creature, trying to ignore his growing fear. “Stop bothering me, Bill.”

 Bill looks at him, floating a couple of feet above him, and blinks once. “Nope. I did consider it, but nope.” He taps Dipper on his forehead. “You’re more interesting.”

 He tries not to wonder why Bill is more interested in him than in his sister. “Look, just – just go away, Bill. You don’t scare me. I’m not some kid anymore.” He’s an adult now, technically, although half the time he doesn’t feel like it.

 Bill looks him up and down. “Are you sure?”

 Dipper looks down at himself, worried for a moment that Bill has turned him into his twelve-year-old self somehow. But no, he sees his usual self, a freshman at college who was up until 2 AM trying to finish an essay and decided to lie down on his bed for a brief nap. “Yes?” he replies.

 “Huh.” Bill somehow manages to shrug. “If you say so, Dipper!”

 He folds his arms. “Yeah, well, I do say so. Now go away, Bill. I’m still not making a deal with you or whatever it is you want.”

 Bill has been looking at him, his triangular body tilted slightly as if in thought. “If you are an adult, Dipper, that means you’ll be more fun now.”

 “What?” More fun? What is Bill talking about? “Look, didn’t you hear me? I’m not interested in making a deal! You’re not bringing the Nightmare Realm to my world!”

 Bill floats closer, his eye only inches away from Dipper’s. “I’m sure there are things that you want, Dipper. Things that I can give you.”

 He lets out a snort. “The only thing I want is to finish my essay.” He glares at Bill. “And that’s not an offer, if that’s what you’re thinking.” He can fail a class if it means Bill doesn’t get what he wants.

 “I wasn’t talking about your essay.” Bill’s voice has lost some of its eerie cheerfulness, and the triangle demon manages a purr. “I was talking about things that you want, Dipper. Deep down. In the depths of your tiny little human brain.”

 “What?” Dipper blinks. “I don’t – what the hell are you talking about?” Bill can’t be talking about – he can’t have realised – no, not that.

 One black, smooth and oddly cold hand rests on his bare arm, the fingers tracing a path down his skin. Bill chuckles, his voice deeper now. “I think you know, Dipper. I got it from your brain, after all!” That last exclamation is more like the manic, cheerful Bill that Dipper is familiar with. It somehow manages to be reassuring.

 “Leave me alone!” he shouts, pulling his arm away.

 “I think we both know that I won’t,” Bill tells him, floating around Dipper as Dipper tries to turn away from him. “Come on. You want something. I can give it to you.” His voice is quiet now. Deep. Seductive.

 Dipper shudders, even as part of him perks up. “No, I don’t.”

 Bill chuckles, sending shivers down Dipper’s spine. “Don’t lie to me, Dipper. I can see into your mind.”

 The cold fingers close around his wrist, and Dipper gasps as he feels them stretch until they slide up his arm. They’re still cold, but it’s a gentle touch. “What are you doing?”

 “What you want me to do,” Bill murmurs, still floating only inches away. His other arm has stretched until it can wrap around Dipper’s other arm. He pushes Dipper’s arms back until they’re touching, and then Bill wraps one of his arms around Dipper’s wrists, and lets go with the other.

 Dipper struggles in the hold of Bill’s…arm? It doesn’t feel like Bill has fingers anymore, and the end of his free arm is now a stump. Did they become tentacles? “This isn’t what I want!”

 Bill taps against Dipper’s left temple with his free tentacle-arm. “Except it is.”

 Brief images flash through Dipper’s mind. He’s always been good with the internet, and finding answers to his questions. So it didn’t take him long to find porn websites with pictures and videos of the sort of thing he found himself interested in. Men touching men. Men kissing men. Men fucking men. Men fucking men roughly. Men fucking men roughly while bound with rope or handcuffs. Dipper whimpers as the porn he’s seen flashes before his eyes, and he realises he’s getting hard.

 “See?”

 He blinks, and instead of naked bodies he’s seeing Bill. Bill, who has Dipper’s hands held tight behind his back, and no matter how much Dipper struggles, isn’t releasing his hold on him. “I want that,” he admits, “but not from you.” How could he? Bill is a _triangle,_ he probably doesn’t even have a penis. Dipper, far too curious for his own good, glances at the area between Bill’s spindly legs. It’s all smooth and yellow. No, definitely not a penis.

 He feels oddly disappointed.

 Bill laughs. “Let me convince you. Come on, you’re curious. Admit it.”

 He remained quiet, and frowns when Bill glows for a moment. The tentacle-arm around his wrists throbs for a moment. “What – what did you do?”

 Bill’s grin widens. “Sped things up a little.”

 He looks down at himself again, and begins struggling to get out of Bill’s tight grip. He’s naked, his bare feet standing in the grass. His cock is half-hard, and he feels his cheeks burn. No, he’s not enjoying this. Not one bit.

 “Oh, stop it, Dipper,” Bill tells him, his tone light. “What are you so worried about?”

 Dipper lets out a laugh. “You’re a crazy demon trying to destroy my world.” He looks up at Bill. “Why do you _think_ I’m worried?” He steels himself. He’s still Dipper Pines, and no matter what, he won’t let Bill win. “But it doesn’t matter how much you try to hurt me, I’m not making a deal with you.”

 Bill is silent for a moment, and Dipper thinks he’s gotten through to him. Then the triangle bursts out laughing. “Oh, Dipper,” he says, his yellow body still shaking with mirth. “Who said anything about hurting you?”

 “What?” Dipper asks, and then he sees Bill’s legs stretch and elongate. They reach for him, like tentacles, and they coil around his thighs. “Hey!” He struggles again as the two tentacle-legs move his thighs to spread his legs, but it’s useless. “What are you doing?”

 “Nothing you don’t want,” Bill informs him. “Now shush, I’m focusing. I haven’t not hurt humans in a long time, and your bodies can be very fragile.”

 Dipper grunts. His legs are spread wide on the grass, but not uncomfortably so. He doesn’t want to think about why Bill wants him standing like this. “What makes you think I even want this?” he spits.

 Bill blinks at him. “Your own mind, of course.” With his free tentacle-arm he taps Dipper’s temple again.

 It’s more of the porn Dipper has found, but now it’s the dirtier, the wronger kind he tries to ignore he likes. The kind where men are tied up against their will, their bodies used for pleasure as they start to enjoy it too. The kind where he has to resort to hentai to really scratch that itch of powerful creatures taking men, no matter how much those men struggle, and filling them with tentacles until those men are begging for more.

 He’s panting when another tap makes those images fade. “No, not that.” His cock is fully hard now, all because of those mental images.

 “I’m just trying to make your dream come true, Dipper!” Bill tells him cheerfully. “Well, not really, because this is still a dream. But perhaps if we made a deal…”

 “No!”

 “No, you’re right,” Bill replies, unfazed by Dipper’s outburst. “I should prove I can keep up my side of the bargain.” The tentacle-arm that had been brushing his temple slithers down his face, and then down his back. It slides further and further down until it slips between his cheeks.

 Dipper jerks forward, trying to escape the strange sensation. The tentacle-arm is still cold as it rubs up and down across his skin. “Wait.”

 “It’ll be fine, Dipper,” Bill tells him, trying to sound reassuring. “It’ll be wonderful.”

 The tip of the tentacle pushes inside of him. It’s small, like a finger, and it goes in without problems. The rubbing has warmed it up a little, but it’s still chilly. Dipper hisses as it slips in further and further. It doesn’t hurt, and he’s very relieved about that. If this is what Bill wants to do to him, he can take it.

 “See, that’s not so bad, is it?” Bill’s voice is soothing. The coils around his thighs move a little, as if they’re caressing him. “Just relax, Dipper. You’ll need to.”

 Then he feels it. The swelling. He thinks he’s imagining it first, but no, the tentacle-arm that’s now a couple of inches inside of him is growing bigger. He can feel his hole stretch around it. “What the hell!” he shouts, trying to jerk his hips out of the way, but the tentacles around his thighs keep him firmly in place.

 “I am trying to make you feel good!” Bill tells him. “I can’t do that if you keep struggling, so I suggest you stop it.”

 The coils around his wrists and thighs tighten painfully, until it’s too much and Dipper swears at Bill. He stops struggling, panting from the exertion. He’ll save his strength for now.

 Bill watches him, then nods. “Good boy, Dipper. I mean, good man. Just let it happen.”

 He groans as the tentacle-arm slides deeper and deeper, filling him up. The tip is flexible, rubbing inside of him, and he gasps as it rubs across his prostate. “Hnng!”

 “Ah, there it is!” Bill exclaims gleefully, the yellow triangle bouncing up and down a few times, without moving his tentacle limbs too much. “Oh yes, this will make things so much easier.”

 The tip keeps rubbing and stroking him, and oh God, it feels good. It feels so good, and Dipper is trying not to moan. His cock is aching with the need to be touched.

 The tentacle-arm inside of him is still growing, and the stretching is getting painful now. “Stop,” he whimpers, hanging his head.

 “Stop? I’ve barely begun!” Bill tells him.

 “No, it’s too big.” He hisses in pain as the tentacle-arm grows larger. “You’ll tear something!” Much to his surprise, he feels the tentacle-arm stop swelling.

 Bill tsks in front of him. “Human bodies…I thought you could take more than that. But very well, my goal is to make you feel good, after all.” The tentacle-arm goes back to rubbing across his prostrate. “Like this, right, Dipper?”

 He tries to keep his mouth closed, not wanting to let any moans escape, but when Bill shoves the arm in hard and fast, he lets out a strangled moan. It’s half-pleasure, half-pain.

 “You have to tell me if it feels good, Dipper, or I might end up hurting you.” Bill’s voice sounds sugary sweet. “And I don’t want to do that.” The tentacle-arm begins to undulate inside of him, its smooth surface pressing and rubbing over his prostate.

 “That’s good!” he manages, then whimpers. It is unbelievably good. He’s never been this full before.

 Bill looks smug. “Wonderful, Dipper. I will just keep going, then. Unless you want me to do something else?”

 Dipper can only moan, closing his eyes. Maybe if he can pretend Bill isn’t here…

 The tentacle-arm inside of him stops moving, and shrinks until it is thick as a finger. “Dipper, look at me. Look at me, or I’ll hurt you.”

 He can take pain, and he shakes his head. Then, the tentacles that are coiled around his thighs start to move, and he feels the two tips brush against his hard cock. “Oh!” That feels very good, to have something rub against it. But when the two tentacles keep moving, still coiled around his thighs, but now also coiling around his cock while the other winds itself around his balls, Dipper becomes nervous.

 “Open your eyes, Dipper,” Bill purrs.

 Dipper shakes his head again, bracing for pain. When the tentacles tighten, hot pain shoots up his spine, and he wants to bring his legs together and curl into a protective ball, but he still can’t move his arms and legs. He screams until he opens his eyes, and then the tentacles release him. The pain still throbs through his body.

 Bill is smiling at him. “See, that wasn’t so bad, was it?” The tentacles that only seconds ago were the source of his pain, are now rubbing and stroking across his balls and cock soothingly.

 Dipper groans. The pain fades into an ache, and with the caresses from the smooth tentacle-legs, his cock is soon achingly hard again. He tries not to think that maybe he kinda _liked_ being in pain before being given pleasure.

 Bill’s smile widens a little. “Now, be a good young man and keep looking at me. I don’t ask much, do I? In fact, I’m not asking for anything. I’m simply _giving_ you what you want, Dipper. You should be grateful.”

 The tentacle around his cock is stroking him in an even tempo, and he finds himself thrusting into its grip. He’s panting now, still trying not to moan or whimper.

 “Whoops, silly me, almost forgot to fix the most important thing!” Bill exclaims, laughing.

 Before Dipper can ask what, he feels the tentacle-arm inside his ass swell again. He can’t help but moan at how _good_ it feels to be filled up again, and even the stretch of his hole around it is a pleasant burn now. But the growing doesn’t stop; Bill makes his tentacle thicker than before. Dipper’s eyes grow wide; he can’t take this! “Enough!” he sobs, breathing hard.

 Bill starts thrusting the tentacle-arm in and out of Dipper. “I think your body can learn to accommodate more than this. Interesting.” His eye sweeps down Dipper’s body before meeting his eyes again. “That should be fun to explore.”

 “Fun?” Dipper moans. He can’t help it. He’s got one tentacle wrapped around his cock, pumping up and down with a nice, tight grip. Then there’s a tentacle stroking his balls, which isn’t nearly as pleasant as having his cock fondled, but still very enjoyable. And then there’s a tentacle that’s now as thick as someone’s lower arm thrusting in and out of him. Fucking him. Filling him just right. Oh God, it feels amazing.

 “Oh yes, you and me are gonna have lots of fun!” Bill tells him happily. “You didn’t think this was it, did you? That I thought one dream in which I pleasured you immensely was enough to make you accept my deal?”

 It’s hard to think through the haze of pleasure. “No – no deal,” he whimpers.

 “Exactly.” Bill doesn’t sound surprised. “Bu-ut, I’m thinking, if I do this to you often enough, give you enough pleasure, then eventually you’ll beg me for it.” He smirks. “In exchange for just one thing.”

 Dipper shakes his head. “Never.”

 “That is such a long time.” Bill tuts. He makes his tentacle-arm push down a little firmer inside of Dipper, making him moan louder. “With every second I’m learning more about what you like, and want. You’ve grown into a dirty man, Dipper.”

 He shudders as he grows hotter at Bill’s words. He needs to wake up, but it’s hard to focus when he’s being fucked and fondled so expertly. “Are you finished yet?” he manages between whimpers.

 “Finished? Why, Dipper, I’ve barely begun. You’ll understand once you’ve had time to think about it.” His grip on Dipper’s cock tightens, but it doesn’t hurt. He also starts fucking Dipper faster with his tentacle-arm. “Just think, Dipper. I can give you pleasure like this for the rest of your life. Wouldn’t you like that, hmm? Doesn’t it feel good?”

 It does, it feels incredible, and Dipper suspects that no human man can fuck him like this. “No.” He spits out the word, then groans in pleasure.

 Bill does, indeed, not look impressed. “I have time, Dipper. I’ll show you I can be nice. I’ll even let you come this time. In fact, I’ll let you come right…now.”

 *

 He wakes up with a start, his heart racing, his entire body hot, with his bedsheets sticking to his body. To his dismay, he finds it’s not _just_ sticking to his body because of sweat.

 “Ah, finally, you’re awake! It was getting kinda awkward, dude.”

 He turns his head, actually surprised to see his roommate, Kevin, sitting on his own bed. The blue light from the laptop is a shining beacon on his face, and Kevin takes his headphones off. “What?”

 “Your, er, y’know? Your dream?” Kevin gestures vaguely at Dipper’s sheets. “You started talking, so I figured I’d put on some Netflix.”

 “Right, right,” Dipper manages. “So, er, did I say anything in particular?”

 Kevin laughs. “What, like a name? No, dude. It was – I don’t know, I didn’t understand it. Sounded like Latin.” He shrugs. “Hey, I’m not judging.” He puts his headphones back on. “But I’m going back to Daredevil now. Night, Dipper.”

 “Yeah, night.” He lies back down, and listens to the tinny sound from Kevin’s laptop. It doesn’t sound like demonical laughter. It doesn’t.  


End file.
